Heating of fluids



July 7, 1936. J, B, HEID 2,046,897

HEATING OF FIKUIDS Filed Sept. 22, 1934 2 Sheets-Sheet 2 I I (5f FIG. 3

INVENTOR 9i JACOB BENJAM N HEID BY d TTOR Y Patented July 7, 19362,048,897 HEATING or mum's Jacob Benjamin Held, Chicago, 111., assignorto Universal Oil Products Company, Chicago, 111., a corporation ofDelaware Application September 22, 1934, Serial No. 745,095

4 Claims.

This invention particularly refers to an improved furnace for heatingfluids which is particularly adapted for heating hydrocarbon oils 1 tothe high temperatures required for their pyrol lytic conversion and isparticularly advantageous as applied to the simultaneous treatment oftwo or more separate streams of the same or different hydrocarbon oils.

One of the principal advantages of the present 10 invention is the wideflexibility of operation which it permits. The furnace structure andmethods of operation provided by the present invention are adaptable tothe treatment of a single stream of fluid or to the simultaneoustreatment of two 15 or more streams of the same or different fluids. Asapplied to the treatment of a single stream of fluid the features of thepresent invention permit independent control of the heating conditionsat various points along the path of flow of the 20 fluid through theheating coil or fluid conduit, thus permitting accurate control of theheating curve, which control is particularly desirable in the conversionof hydrocarbon oils. As applied to the simultaneous treatment of morethan one 25 stream of the same fluid, the present invention permits thetreatment of larger quantities of fluid in a single furnace than isotherwise possible without excessive pressure drop through the fluidconduit, due to friction. It also provides 30 for subjecting at leasttwo streams of the same fluid to substantially equal heating conditionsand further provides for fairly accurate control over the type ofheating curve obtained for the total fluid undergoing treatment,although not to so 35 great an extent as when applied to the treatmentof a single stream of fluid. As applied to the simultaneous treatment ofmore than one stream of difierent fluids, the present invention permitsaccurate and independent control over the heat- 40 ing conditions towhich each stream is subjected and permits fairly accurate andindependent control over the type of heating curve obtained for eachstream.

Another important feature of the present in- 45 vention is the provisionfor obtaining exceptionally high rates of heat input to certain portionsof the fluid conduit and the materials passing therethrough. This isaccomplished by subjecting each tube in those portions of the fluidconduit wherein high rates of heating are desired Y to heating by directradiation from the flames and hot refractory walls of the furnace so asto obtain an average rate of heat input around the entire periphery ofthe tube which approaches 55 the maximum permissible rate of heating atany point thereon, thereby materially increasing the average rate ofheating. This is accomplished without sacrificing furnace efflciency bymeans of employing other heat absorbing surfaces beyond the zones of thefurnace wherein said high rates of heating are employed so as todecrease the temperature of the combustion gases leaving the furnace.

The accompanying diagrammatic drawings (Fig. 1) is a sectional elevationof one specific type of furnace structure embodying the features andadvantages of the present invention, and

Figs. 2, 3 and 4 of the drawings illustrate several of the many possiblespecific flows which may be employed through the fluid ,conduit of thefurnace structure shown in Fig. 1.

' Referring particularly to Fig. l of the drawings, the main furnacestructure comprises side walls I and 2, a roof 3, a floor 4 and endwalls, which are not illustrated in the particular view of the drawingshere shown. The interior of the furnace is divided, by means of bridgewalls 5 and 6 extending between the end walls of the furnace, into twoseparate combustion and heating zones 1 and 8 and a centrally locatedfluid heating zone 8.

A fluid conduit or tube bank ll comprising, in the case hereillustrated, two vertically parallel rows of horizontally disposed tubesIn is located within combustion and heating zone I midway between sidewall I and bridge wall 5. Another tube bank l2 which, in the case hereillustrated, is similar to tube bank II and comprises two verticallyparallel rows of horizontally disposed tubes I0 is similarly located incombustion and heating zone 8 midway between side wall 2 and bridge wall6. Another tube bank l3 comprising,

in the case here illustrated, asingle horizontal row of horizontallydisposed tubes i0 is located adjacent the floor of combustion andheating zone I and a similar tube bank I4 is located adjacent the fioorof combustion and heating zone 8. Another tube bank l5, comprising, inthe case here illustrated, a single horizontal row of horizontallydisposed tubes I0, is located adjacent the roof of the furnace, portioniii of this bank being located above combustion and heating zone 1,portion l5" above combustion and heating zone 8 and portion I5' abovethe centrally located fluid heating zone 9. Another tube bank 16comprising, in the case here illustrated, a plurality of superimposedhorizontally parallel rows of horizontal tubes I0 is located withinfluid heating zone 9 of the furnace.

Combustible fuel and air is independently supplied in regulatedquantities to each of the separate combustion and heating zones I and 8through burner ports H which are located on opposite sides of each ofthe tube banks II and H. The fuel may be of any desired form, such asoil, gas or pulverized solid fuel, and is supplied through suitableburners, the tips of which are indicated at l8. Air for atomization mayalso be supplied through the burners and additional air for combustionas well as any desired quantity of excess air may be supplied througheach of the burner ports ll. The total quantity of fuel supplied to eachcombustion zone as well as the relative proportion of fuel and air isindependently controlled and preferably independent control is alsoexerted over the quantity of fuel and the proportion of fuel and airsuppliedthrough each burner port, so that substantially the sameor-different firing conditions may be maintained in each combustion zoneand so that substantially uniform or different firing conditions may bemaintained in the locality of each burner port. In this mannerindependent control is exerted over the heating conditions about fluidconduits I I, I3, and I as compared with the heating conditions employedabout the fluid conduits l2, l4, and I5" and also means are afforded foremploying substantially the same or for varying the heating conditionsabout different portions of each of the fluid conduits II and I2.

Predominantly radiant heat is supplied to opposite sides of each tube ofbanks II and I! by direct radiation from the materials undergoingcombustion in combustion zones I and 8, respectively, and from the hotrefractory wallsof the furnace. The tubes of banks l 3 and II are heatedon one side by direct radiation from the materials undergoing combustionand the hot refractory walls of the furnace and on the opposite side ,by

radiant heat reflected from the floor. The tubes.

of bank l5 are subjected to heating on one side by direct radiation fromthe materials undergoing combustion and the hot refractory walls of thefurnace and on the opposite sideby radiant heat reflected from the roof.Eachof the tube banks and particularly bank l5 are also subjected toappreciable heating by convection. The hot combustion gases pass fromcombustion and heating zones 1 and 8 over bridge walls 5 and 6,respectively, to commingle above fluid heating zone 9 and the commingledgases pass downward through this zone imparting fluid heat to the tubesof bank IS with which they come in contact. The combustion gases maypass from fluid heating zone i through flue 19 to a suitable stack (notshown).

It will be apparent from theabove that the heating conditions obtainedin tube banks ll, l3, and I5 are the result of the conditions of firingemployed in combustion and heating zone I while the heating conditionsemployed about tube banks I2, l4, and I5" are the result of theconditions of firing employed in combustion and heating zone 8. Also,the heating conditions obtained in tube banks l5 and I6 are the resultof the conditions maintained in both of thecombustion and heating zonesI and 8. Therefore, the heating conditions and rates of heat inputobtained in tube banks l5"' and [6 are not controllable, independent ofthe heating conditions maintained about other portions of the fluidconduit. However, tube banks such as l5' and/or 16 greatly improve thethermal efliciency of a furnace of the nature disclosed, since theypermit the use of lower flue gas temperatures and, preferably, in thepresent invention tube banks l5 and/or 15" are employed in that stage ofthe heat treatment wherein accurate control of the heatingcondistructure above described and illustrated, the various tube banksin each of the Figs. 2, 3, and 4 are designated by the same referencenumbers as in F18. 1.

Fig. 2 is representative of the type of flow which 5 may be employed forsimultaneously subjecting two separate substantially equal streams ofthe same oil to substantially equal heating conditions. The stream oftotal oil to be heated is supplied from any suitable source through line24 and 10 is divided into two substantially equal streams which passthrough lines 25 and 25', controlled by the respective valves 26 and26', into equal sections l6 and "5'', respectively, of fluid heatingbank l6. Each stream of oil passes in a general upward direction throughthis bank of tubes countercurrent to the general direction of flow ofthe combustion gases passing through this zone of the furnace, the oilfrom bank l6 passing from the uppermost row of tubes of this bankthrough line 21 into tube bank l5, flowing through adjacent tubes ofthis bank in series in a general direction countercurrent to thedirection of firing, while the stream of oil from tube bank l6" passesin a similar manner through line 25 21' and tube bank I 5". The streamof oil from tube bank I5 is transferred through line 28 to tube bank l3,flowing in series through adjacent tubes in this bank to be transferredtherefrom through line 29 to the upper portion of tube bank 3,0 I I. -Ina similar manner, a stream of oil from tube bank l5" passes through line28' to tube bank l4, flowing in series through adjacent tubes in thisbank to be directed therefrom through line 29' to the upper portion oftube bank I 2. The two sepa- 35. rate streams of oil pass throughadjacent tubes in alternate. rows of the respective tube banks H and I2.in a general direction concurrent to the direction of firing, and aredischarged therefrom through the respective lines 30 and 30' to'40.

subsequent portions of the system not pertinent to the presentinvention, the two streams of oil preferably being commingled shortlyafter their discharge from the furnace.

In Fig. 2, by controlling the flow of the oil supplied to the heatingcoil so that substantially the same quantity of oil is continuouslysupplied to each of the two separate streams and bymaintainingsubstantially uniform firing conditions in each of thecombustion and heating zones eachof the two separate streams of oil maybe subjected to substantially equal hea'fing conditions. Fig. 3illustrates one of the many specific forms of flow which may be employedfor the treatment of a single type of hydrocarbon oil employing a singlestream and series flow throughout the heating coil. The oil to betreated is supplied through line 3| to tube bank l6 flowing in seriesthrough adjacent tubes and adjacent rows of tubes in this bank in ageneral upward direction countercurrent to the general direction of flowof the combustion gases through this zone of the furnace. The oil passesfrom the uppermost row of tube bank I 6 through line 32 to one end oftube, bank l5, passing in series through adjacent tubes of this bank toits opposite end from which it is directed from line 33 to tube bank l3wherein it flows in series through adjacent tubes in this bank and fromwhich it is directed through line 34 to the upper portion oftube bankII. The oil flows in series through the tubes of bank II which, in thecase here illustrated, comprises a single vertical row of horizontaltubes, and is directed therefrom through line 35 to and through tubebank It, passing through the adjacent tubes of this bank in series andbeing directed therefrom from line 36 to the lower portion of tube bankI: wherein the oil passes in a general upward direction through adjacenttubes in alternate rows of this bank to be discharged from the upperportion of tube bank I! through line 31 to subsequent portions of thesystem not pertinent to the present invention.

In Fig. 3, by employing more severe heating conditions in the combustionzone on the left hand side of the furnace (adjacent tube banks H and I3)than in the combustion zone on the opposite side of the furnace(adjacent tube banks I2 and it) the oil undergoing treatment may besubjected to a substantially progressive increasing rate of heating fromthe time it enters the furnace until it leaves tube bank It and may thenbe subjected to what are ordinarily termed soaking' conditions in tubebanks It and i2. This type of treatment has been found particularlydesirable for relatively low-boiling distillates such as straight-rungasoline, naphtha, pressure distillate bottoms and the like.

Fig. 4 illustrates one of the many forms of flow which may be employedfor the simultaneous treatment of two separate streams of difierenthydrocarbon oils, each stream being subjected to independentlycontrolled heating conditions. One stream of oil enters the lowerportion of tube bank It through line 38, passing in series throughadjacent tubes and adjacent rows of tubes of this bank in a generalupward direction, it then passes. from tube bank It through line 39 totube bank l3 through which it flowsv inseries through adjacent tubes andis then directed through line 40 to the upper portion of tube bank H.The oil passes in series through adjacent tubes in alternate rows oftube bank I I in a general direction concurrent to the direction offiring and is directed from the lower portion of bank ll through line Hto the left-hand side of bank l wherein it passes in series throughadjacent tubes of this bank in a general direction concurrent to thegeneral direction of flow of the combustion gases, to be discharged fromthe right-hand sideof this bank through line 42 to subsequent portionsof the system not pertinent to the present invention; The other streamof oil, of dlfierent characteristics, which is to be simultaneouslysubjected to independently controlled heating conditions of the samefurnace, is directed through line 43 to the left-hand side of tube bankI5" passing in series through adjacent tubes of this bank in a generaldirection countercurrent to the general direction of flow of thecombustion gases. The oil then passes from the right-hand side of tubebank 15" through line 44 to one side of tube bank I4, flowing in seriesthrough adjacent tubes of this bank to the opposite side thereof fromwhich it is directed through line 45 to the upper portion of tube bank I2. The oil then passes in a general downward direction through adjacenttubes in alter-' na-te rows of tube bank ii to be discharged from thelower end of this bank through line 45 to subsequent portions of thesystem not pertinent to the present invenion.

A flow, such as illustrated in Fig. 4, may be utilized to advantage, forexample, by subjecting an intermediate oil such as, for example, refluxcondensate, gas oil or the like to conversion under relatively severeheating conditions by passing it in series through tube banks l6, l3,II, and I! while employing somewhat milder heating conditions for thetreatment of higher boiling oil such as crude oil, topped or reducedcrude, 5

fuel oil or residual oils generally, which higher boiling oil is passedin series through tube banks l5", l4, and I2.

It will be understood, of course, that the present invention is notlimited to the specific form of furnace illustrated and above describednor to the specific form of fluid conduits provided in the furnaceillustrated nor to any or all of the three specific flows through thefluid conduits illustrated and above described. For example, either orboth of tube banks II and I2 may comprise a single row instead of adouble row of tubes and any one or more of the various tube banks l3,l4, and I5 may comprise twoor three parallel rows of tubes instead 01' asingle row. The flow through the fluid conduits may also be so arranged,when desired, that more than two streams of the same fluid may be heatedsimultaneously each under substantially equal heating conditions or sothat more than two streams of 35 diiferent fluid may be heatedsimultaneously, each stream being subjected, when desired, to differentheating conditions.

I claim as my invention:

1. In a furnace having walls forming a combustion and radiant heatingzone, the combination of fluid heating means, comprising a vertical rowof horizontal tubes, centrally disposed in said zone, a horizontal rowof serially connected, horizontal tubes in the lower portion of saidzone beneath said fluid heating means, a second horizontal row ofserially connected, horizontal tubes in the upper portion of said zoneabove said fluid heating means, and means for supplying fuel and air tosaid zone on opposite sides of said fluid heating means.

, 2. In a furnace having a pair of spaced vertical walls, a roof and afloor, the combination of a vertical row of horizontal tubes between andspaced-from said walls, a horizontal row of serially connected,horizontal tubes adjacent the roof above said vertical row of tubes, ahorizontal row of serially connected, horizontal tubes adjacent thefloor beneath said vertical row of tubes, and means for burning fuel inthe space between said vertical row and each of said walls.

3. A furnace comprising walls forming a pair of combustion zones and aconvection heating zone, heating tubes in the convection zone and meansfor passing combustion gases from both said combustion zones through theconvection zone, a vertical row of horizontal heating tubes in each ofthe combustion zones, means for firing each of the combustion zones onopposite sides of the vertical row of tubes therein, a horizontal row ofheating tubes in the lower portion of each of the combustion zones belowthe vertical row of tubes therein, and a horizontal row of tubes in theupper portion of the furnace and having tubes disposed in each of thecombustion zones.

4. The furnace as defined in claim 3 further characterized in that theconvection zone is positioned between the combustion zones and in thatthe horizontal row of tubes in the upper portion of the furnace includestubes disposed above the 70 convection zone.

JACOB BENJAMIN HEID.

DISCLAIMER 2,046,897.Jac0b Benjamin Hez'd, -Chicag0, I11. HEATING OFFLUIDS. Patent dated July 7, 1936. Disclaimer filed September 11, 1937,by'the patentee;

the assignee, Universal Oil Products Company, assenting. Hereby entersthis disclaimer to claims 1, 2, and 3 of said patent.

[Ofiicial Gazette October 5, 1937.]

